This invention relates to wheel covers, which term herein includes trim rings and the like adapted to be removably attached to a vehicle wheel, and in particular relates to means for securing such covers to an axial flange of the wheel.
Heretofore great effort has been expended in the development of wheel covers and retention means for positively securing the covers to the wheels so as to withstand various tests and road conditions tending to jar the covers loose. In consequence, considerable difficulty is often experienced when it is desired to remove the cover, as for example to replace or repair a dented or otherwise damaged cover or to change a tire. The retention means may be so effective that the cover cannot be removed without serious injury to the parts, with the result that after one or two removals, the retention means and sometimes the cover are damaged beyond use.
When a wheel cover is properly located coaxially on a wheel, the force required to secure the cover to the wheel is appreciably less than when the cover is secured eccentrically. Also, when a cover is inadvertently secured eccentrically to the wheel, not only do the resulting unbalanced centrifugal forces tend to throw the cover from the wheel but tire wear is accelerated and the vehicle ride can be objectionable.
In order to secure the cover coaxially to the wheel, it has been the practice heretofore to secure the cover at a number of circumferentially spaced locations, as for example, six or eight. Thus, if a careless mechanic fails to force one of the conventional retention devices properly against the wheel, the circumferentially adjacent retention devices assure a reasonably coaxial attachment between the cover and wheel.
A significant contribution of the present invention has resulted from the realization that the numerous retention devices required heretofore are merely to assure reasonable coaxial attachment between the cover and the wheel, whereas if care is taken to attach the cover coaxially, a nominal number of conventional retention devices, as for example, one-half the number employed heretofore, will secure the cover positively to the wheel under all typical driving conditions.
It is an important object of the present invention to provide improved retention means for a vehicle wheel cover whereby alternate retainers may comprise a set of locating devices which are only nominally effective by themselves as retention devices and which are therefore easily removable from the wheel, but which are effective in assuring that the cover is located and secured coaxially on the wheel. In consequence of reducing the number of effective retention devices, the cover may be pried from the wheel with far less effort than has been required heretofore, because only nominal force is required to pry the remaining locating devices from the wheel.
In order to remove a wheel cover from a vehicle wheel, it is customary to insert a heavy screwdriver or other pry between the cover and wheel at one circumferential location and pry the cover loose. Usually the free space between the prying tool and the vehicle wheel or tire is quite limited, with the frequent result that when the tool swings into engagement with the tire at the limit of the available prying movement, the retention device merely yields resiliently without in any way being dislodged from its attachment with the wheel rim. When the prying tool is removed, the retention device returns resiliently to its former attached position. On the other hand, if the prying operation is successful, the diametrically opposite retention device is often deformed beyond its elastic limit, with consequent damage to the overly stressed retention device and impairment of its attachment effectiveness for successive use.
Other important objects are to provide an improved wheel cover that is effective to limit the extent of eccentricity between the cover and wheel, and to provide such a cover which narrowly limits the amount of resilient movement that can be imparted to the retention means during its attachment to the wheel or removal therefrom and which thereby prevents bending of the retention device beyonds its elastic limit.
Another object is to provide an improved retention device comprising a sharp barb adapted to embed into an axial flange of the wheel to effect the retention and which thus has the retention effectiveness of conventional devices, but which comprises cam means for disengaging the attachment between the barb and wheel flange when forced axially beyond a predetermined limit toward the wheel, thereby to achieve coaxial alignment between the cover and wheel by assuring that each of the circumferentially spaced retention devices when attached to the wheel lies in substantially the same plane normal to the wheel axis.
Other and more specific objects are to provide a retention means comprising a formed ribbon of spring steel secured to the wheel cover and having a wheel engaging barb on a resiliently hinged arm adapted to urge the barb radially outward with spring force into biting engagement with the axial wheel flange. The axial arm extends outward beyond the barb from a spring hinge connection with a fixed portion secured to the wheel cover and is provided with a locating arm that extends radially outward to engage a radial flange of the wheel when the cover is forced axially toward the wheel beyond a predetermined limit.
In a typical wheel construction, the aforesaid radial wheel flange merges arcuately with the axial wheel flange, which the barb engages, to provide a rounded cam surface. The locating arm of the retention device is dimensioned to engage a radially outer portion of the cam surface when the cover is at said predetermined limit and to slide by cam action radially inward along the cam surface when the wheel cover is forced axially toward the wheel beyond said limit. In consequence, the axial barb carrying arm is resiliently forced radially inward to detach the barb from its biting engagement with the axial wheel flange, releasing the cover to enable its axial outward movement until reverse movement of the locating arm radially outward along the cam enables the barb to re-engage and bite into the wheel flange.
During attachment of the wheel cover to the wheel, the barb frictionally engages the axial wheel flange and tends to resist the axial inward movement of the cover to the attached position. Thus, the axial barb carrying arm tends to drag behind the wheel cover as it moves to the position whereat attachment is desired. It is accordingly another specific object of the invention to provide a backup projection of the wheel cover closely spaced axially outward from the locating arm to limit the extent to which the latter and the barb carrying arm secured thereto can lag behind axial inward movement of the wheel cover.
By reason of the radial outward spring force of the axial barb carrying retention arm that urges the barb into engagement with the wheel flange when attached thereto, the axial barb carrying arm in its unstressed condition would extend obliquely to the axis of the wheel and cover, such that without some provision to the contrary, the locating arm would in some instances engage peripheral portions of the wheel and interfere with attachment of the cover. Another object, therefore, it to provide an axial extension of the barb carrying arm that lies radially inward of the back-up projection to limit radially outward movement of the latter axial extension and barb carrying arm.
Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.